Experimental data on the effect of added solutes upon sickle-cell hemoglobin gelation will continue to be accumulated. Measurements will be made of the effect of sickle-cell hemoglobin aggregation upon the oxygenation of sickle erythrocytes under a variety of experimental conditions. A combined experimental and theoretical study of the self- association of retinol and retinaldehyde in non-polar solvents will be initiated. Theoretical studies of structure-function relationships in hemoglobin will continue.